<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>函数提升</title>
</head>
<body>
   <script>
   fn()
   console.log(fun)
   function fn(){
   console.log('函数提升');
   }
   var fun=function(){
     console.log('函数表达式');
   }
   </script>
</body>
</html>